210 HISTORICAL PALAZONTOLOGY. 
istic of the Muschelkalk. In this beautiful species, the flower- 
like head is supported upon a rounded stem, the joints of 
which are elaborately articulated with one 
another; and the fringed arms are com- 
posed each of a double series of alter- 
nating calcareous pieces. The Paleozoic 
Urchins, with their supernumerary rows of 
plates, the Cystideans, and the Pentremites 
have finally disappeared ; but both Star- 
fishes and Brittle-stars continue to be rep- 
resented. One of the latter—namely, the 
Aspidura loricata of Goldfuss (fig. 143)—is 
44 
Bs 
ane 
C2 
Se 
Fig. 143.—Aspidura loricata, a Triassic Ophiuroid. 
Muschelkalk, Germany. 
highly characteristic of the Muschelkalk. 
The remains of Articulate Animals are 
not very abundant in the Tnias, if we except 
the bivalved cases of the little Water-fleas 
(Ostracoda), which are occasionally very 
plentiful. There are also many species 
Ass of the horny, concentrically-striated valves 
Fig. 142.—Head and of the L“stherie@ (see fig. 122, 6), which 
ee es He might easily be taken for small Bivalve 
The lower figure shows Molluscs. :.The “ Long-tailed”. Decapads, 
the articulating surface : 
of one of the jointsofthe Of the type of the Lobster, are not with- 
paca Muschelkalk, out examples, but they become much more 
numerous in the succeeding Jurassic pe- 
riod. Remains of insects have also been discovered. 
Amongst the JZollusca we have to note the disappearance, 
amongst the lower groups, of many characteristic Palaeozoic 
types. Amongst the /olyzoans, the characteristic ‘‘ Lace- 
corals,” Fenestella, Retepora,* Synocladia, Polypora, &c., have 
* The genus Xetefora is really a recent one, represented by living forms ; 
and the so-called Retepore of the Paleozoic rocks should properly receive 
another name (PAyllopora), as being of a different nature. The name 
Ketepora has been here retained for these old forms simply in accordance 
with general usage. 
